Questions & Answers about El descobert és greu.
Because el descobert is being used as a noun phrase, not just as a bare adjective or participle.
In Catalan, it is very common to use el + adjective/past participle to mean the ... thing / the ... situation / the ... concept. So here el helps turn descobert into something noun-like.
So structurally:
- el descobert = the noun phrase
- és greu = is serious
In many contexts, el descobert is a fixed expression, so the article is part of how the phrase is normally said.
Here, it functions as a noun.
On its own, descobert is originally the past participle of descobrir. But in this sentence it is being used substantively, meaning it behaves like a noun.
That is why the sentence works like:
- El descobert = subject
- és = verb
- greu = adjective describing the subject
So even if the word historically comes from a participle, in this sentence you should treat el descobert as a noun phrase.